Eric Jensen, 37, right and Ryan Jensen, 33, brothers who owned and operated Jensen Farms, arrive at the federal courthouse in Denver with family in October 2013.

By Erik Ortiz, Staff Writer, NBC News

Two Colorado brothers whose contaminated cantaloupe farm was tied to 33 deaths in one of the nation’s worst food-borne sickness outbreaks won’t have to serve prison time.

A federal court judge in Denver on Tuesday sentenced Eric and Ryan Jensen to five years’ probation, six months’ house arrest and ordered them to pay $150,000 each in restitution, the U.S. Attorney’s office said.

The farmers had been facing as much as six years in prison and a $1.5 million fine.

The U.S. is believed to have the safest food supply in the world, yet last year 48 million people were sickened by tainted food.

The light sentence was disappointing to folks like Paul Schwarz, 64, of Missouri, whose father died from the listeria outbreak in 2011.

“I’ll accept it but I’m not happy,” Schwarz, who attended the sentencing, later told NBC News. “I think other people should have been sitting there as well.”

The Jensens pleaded guilty in October to six misdemeanor counts of introducing “adulterated food” into interstate commerce. Although they cut a deal with federal prosecutors, it didn't include a recommendation for a lower sentence, The Denver Post reported.

The Jensens’ farm in eastern Colorado on the Kansas border was identified as ground zero for the outbreak. The cantaloupes grown there were responsible for killing 33 people and hospitalizing 147 others across 28 states, prosecutors said.

A lawyer for Eric Jensen said last year the brothers were willing to plead guilty because "it happened on their watch," although they didn’t want the plea to imply there was intentional wrongdoing or they knew about the tainted cantaloupes beforehand.

Prosecutors were also asking for probation, in part, because the brothers met with the families of many of the victims and assisted in the investigation.

The pair’s farm in May 2011 began using the same system to wash potatoes to clean cantaloupes, too. But they neglected to use a chlorine spray that could have greatly cut down bacteria.

“The defendants were aware that their cantaloupes could be contaminated with harmful bacteria if not sufficiently washed,” U.S. Attorney John Walsh in Colorado said in a previous statement. “The chlorine spray, if used, would have reduced the risk of microbial contamination of the fruit.”

Ed Andrieski / AP file

An operator of a fruit and vegetable stand near Denver holds a California-grown cantaloupe for sale at her business in 2011.

The Jensens apologized in court Tuesday, and an attorney for Eric Jensen called them “good, salt of the earth, Americana people,” The Denver Post reported.

Their farm had used a food safety auditor to check its product prior to the tainted cantaloupes being shipped, but the company failed to correct the situation, a federal investigation found.

Schwarz said those third-party auditors should be held liable as well.

The listeria bacteria is found in soil and can cause headaches, convulsions and stiff neck, according to the Centers for Disease Control and Prevention. Older adults, pregnant women and those with susceptible immune systems are most at risk for a fatal infection.

Schwarz said his dad's death should have been prevented.

The elder Paul Schwarz was a spry 92, who had a love for golf and carried a pair of Purple Hearts after serving in World War II in New Guinea and the Philippines.

In September 2011, he came down with flu-like symptoms and was rushed to the hospital. In time, the listeria ate away at his memory and his muscle movement. His legs failed him.